1. Field of the Invention
The present invention relates to a surface acoustic wave filter device.
2. Description of the Related Art
In the related art, for example, in Japanese Unexamined Patent Application Publication No. 2010-11300, various surface acoustic wave filter devices that utilize surface acoustic waves have been proposed as band-pass filters, demultiplexers, and the like included in RF (Radio Frequency) circuits in communication apparatuses, such as mobile phones.
FIG. 9 is a schematic circuit diagram of a surface acoustic wave demultiplexer disclosed in Japanese Unexamined Patent Application Publication No. 2010-11300. As shown in FIG. 9, a surface acoustic wave demultiplexer 100 includes an antenna terminal 101, a transmission side signal terminal 102, and first and second reception side signal terminals 103a and 103b. A transmission filter 104 is connected between the antenna terminal 101 and the transmission side signal terminal 102. Meanwhile, a reception filter 105 is connected between the antenna terminal 101 and the first and second reception side signal terminals 103a and 103b. The transmission filter 104 is a ladder type surface acoustic wave filter and includes a plurality of surface acoustic wave resonators, a plurality of capacitors, and a plurality of inductors. The reception filter 105 is a longitudinally-coupled resonator type surface acoustic wave filter.
The surface acoustic wave demultiplexer 100 includes a transmission filter chip 106 in which a portion of the transmission filter 104 is provided, and a reception filter chip 107 in which a portion of the reception filter 105 is provided. The transmission filter chip 106 and the reception filter chip 107 are flip-chip-mounted on a wiring board that is not shown.
A surface acoustic wave filter device that includes a surface acoustic wave filter chip and a wiring board on which a surface acoustic wave filter chip is flip-chip-mounted as in the surface acoustic wave demultiplexer 100, is desired to have high power durability.